Method of manufacturing a fibrous fabric

ABSTRACT

A method of manufacturing a fibrous fabric in which fibers are injected into a web of fibrous material in a direction substantially normal to a major surface of the web. The web is then impregnated with a binding agent to bond the fibers of the web and the injected fibers. The injected fibers strengthen the web in the direction normal to the web major surfaces and, in the case where the web is constituted from two or more fibrous layers, interlinks the layers. The fibers can be injected by means of a compressed air blower or by electrostatic action between spaced electrodes.

United States Patent Pius Stebler Grillingerstr, Nunninger, Switzerland749,782

Aug. 2, 1968 Oct. 26 1971 METHOD OF MANUFACTURING A FIBROUS FABRIC 9Claims, 2 Drawing Figs.

Inventor Appl. No. Filed Patented References Cited UNITED STATES PATENTS9/1966 Lemelson 156/72 3,477,889 11/1969 Partensky ABSTRACT: A method ofmanufacturing a fibrous fabric in which fibers are injected into a webof fibrous material in a direction substantially normal to a majorsurface of the web. The web is then impregnated with a binding agent tobond the fibers of the web and the injected fibers. The injected fibersstrengthen the web in the direction normal to the web major surfacesand, in the case where the web is constituted from two or more fibrouslayers, interlinks the layers. The fibers can be injected by means of acompressed air blower or by electrostatic action between spacedelectrodes.

PATENTEDBCT 26 [9?! 3 615,967 SHEET 10F 2 Inventor: F/u: 5 72-731. eve,

PATENTEDEIBI 26 1911 4 SHEEI 2 BF 2 Inventor: l'us .STEBLEA, 3 him I p 1W fr-Mae METHOD OF MANUFACTURING A FIBROUS FABRIC BACKGROUND OFINVENTION Varied methods and apparatus are known for manufacturingfibrous fabrics from stranded fibrous materials such as threads, yarns,twines, cords, ropes, strings, tresses, ribbons, braids, hoses and thelike, for meeting industrial demand for shaped bodies formed from suchfabrics. Attempts have been made to give such fabrics, and shaped bodiesmade from them, an adequate breaking strength and resistance to shocknot only in the directions lying in the plane of the fabric but also inthe directions normal of the fabric.

In one known method, mineral, animal or synthetic fibrous material isfed into a swirl nozzle of a compressed air or gas blower. The fibrousstrands assume a helical or spiral formation and the strands in onelayer become entangled with those in the next, so that some cohesionbetween the layers is obtained. The results obtained are, however, notentirely satisfactory because, although the strands are not barbed inany way no reliable interlinking of the layers takes place.

In another known method, superimposed layers of waddinglike and feltlikematerials are are impregnated with adhesive. Cohesion between the layersis the result merely of the properties of the adhesive, interaction ofthe fibers playing no part in interlinking the layers. Despite the useof colloidal, particularly water-soluble, organic, inorganic, hydraulicor bituminous binding agents, the strength of the fabric in thedirection normal to the surface of the fabric is still inadequate.

In the manufacture of glass-fiber fabric, a plurality of threads aredelivered by a reciprocating device onto a rotary drum which performsseveral revolutions during each reciprocation of said device. Thecylindrical fabric so formed is slit open and stretched, and may bedivided into individual pieces of desired dimensions. Cohesion withinthe fabric in the direction normal to the plane of the fabric isobtained since the superimposed threads are fused or coalesced. However,elasticity and the ability of the fabric to bulge" decrease to such anextent that the fabric can not be used in cases where both propertiesare required.

Although this process may be applied to the manufacture of fabric fromsynthetic fibers the continuous individual threads are all aligned, i.e.all extending helically through the cylindrical fabric prior toslitting. Interlinking of the threads is absent, so that the strength ofthe material depends on the adhesion of one parallel thread with thenext, both within each layer and between superimposed layers.

SUMMARY OF INVENTION The disadvantages of the prior art are overcome, inaccordance with the invention, by injecting fibers into a fibrous web ina direction substantially normal to a major surface of the web, andimpregnating the web with a binding agent. The injected fibers providestrength and breaking resistance in the direction normal of the majorsurface of the fabric. If the web is composed of a plurality of fibrouslayers, the injected fibers link the layers together. The impregnationof the web bonds the strands making up the layers with the injectedfibers to produce a fabric which has strength in all dimensions.

The fibrous web or its constituent layers may be made up from strands inthe form of threads, yarns, twines, cords, ropes, strings, tresses,ribbons, braids, hoses and the like. The strands making up the web orthe layers may be woven, knitted or randomly tangled or otherwise.

The invention is not limited to the treatment of substantially flatlayers or webs. Fleeces on cottonwool-type bodies, whose dimensions maybe varied at will, may also constitute the web subjected to theinvention. The strands making up the fibrous web or the layers can beformed from any substance which is capable of being stranded, as may bethe injected fibers, and particularly from animal, vegetable and mineralfibrous materials. Mineral fibers are natural fibers or inorganicsynthetic fibers of mineral raw materials, such as glass, slag, stone,quartz, asbestos, or cermet fibers, and mixtures or compounds thereof.Examples of vegetable fibers are: cotton, kapok, flax, hemp, jute, Ramieor Chinese nettle, sisal, sisal fibers, ixtle, sanfevieria, Manila hemp(zebuor abaca-hemp), piasava, bauginia (apta), esparto, (alfa) andcoconut fiber (coir). Examples of animal fibrous materials are: wool(merino-, colonialand crossbred-wools; crossbred-, cheviot-,cashmere-wools), mohair, natural silk, alpaca (llama) and camelhair.Examples of chemical or synthetic fibers are the manmade threads suchthose of the polyvinyl-, polyamide-, polyacryland polyester-groups, andthe so-called manmade spun fibers (staple fibers) again of thepolyvinyl-, polyamide-, polyacryland polyester-groups. With regard tothe polyvinyls, examples are PeCe, PeCeU, Rhovyl. Examples of thepolyamides are Perlon and Nylon (Trademarks). Examples of the polyacrylsare Dralon, Redon and Dolan (Trademarks). An example of the polyestersis Diolen, and of the polyester manmade spun fibers an example isTerylene (Trademarks).

Suitable binding or strengthening agents have been mentioned above inthe previous section. Any substance is suitable which can be used tostrengthen stranded material and, in particular, adhesives, i.e.substances which, in a thin liquid or pasty layer between the strands orinjected fibers, cement these by means of a setting process. Thisprocess may involve evaporation of a solvent, in interlacingpolymerization though chemical bonds or even in solidification of asmelt. Suitable substances are glue, paste, pap, binders, adhesivedispersions, mastics, adhesive solutions, adhesive cement, solventadhesives, reaction adhesives, heat-sealing adhesives, dry adhesives,coldsetting adhesives, hot-setting adhesives, contact adhesives and wetadhesives.

The invention also provides apparatus for manufacturing a fibrous fabriccomprising means for supporting a fibrous web, means for injectingfibers into the web in a direction substantially normal to a majorsurface of the web, and means for impregnating the web with a bindingagent.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. l is a diagrammaticrepresentation of a machine in which the fibrous web is tubular in formand the fibers are injected into the web from within the tube.

Fig. 2 is a diagrammatic representation of a machine in whichelectrostatic action is used to inject the fibers.

DESCRIPTION OF PREFERRED EMBODIMENTS Embodiment of Figure l: The machineincludes an arrangement for forming a hose from intersecting continuousstrands, splitting the hose, unwrapping it and winding it upon a takeuproller. The wall of the hose may be formed from several concentriclayers which may be interlinked and the wall strengthened by fibersinjected into the wall, which is subsequently impregnated with bindingagent.

In greater detail, the machine has a frame comprising a baseplate l anda vertical wall 2. Compressed air blowers 5 and 6 are mounted on wall 2by brackets 3 and 4, respectively. The blower 5 introduces afibre-carrying airstream into the interior of the hose [8 which is inthe process of being formed. An outlet 7 from a container 10 containinga supply ll of fibers opens into the blower housing and is provided witha metering device in the form of brush roller 9 driven by shaft 8. Theblower 5, which has impeller 12, has a discharge duct terminating adiverging surface 14 surroundingaconical head 15 of hose mandrel 16.Surface 14 and head I5 define together an annular, radially outwardlydirected nozzle 17 such that the fiber-laden airstream emerges radiallyoutwards from duct 13. In order to increase the forces urging the fiberscarried by the airstream against the web constituted by hose 18, thesecond blower 6 is provided with an outlet duct 33 terminating in anozzle 32 within duct 13.

The arrangement for forming a tubular web in the form of a hose,comprises a plurality of spools 19 on each of which is coiled acontinuous strand of fibrous material. The strands may be formed fromorganic or inorganic fibrous substances, suitable substances havingalready been listed, or from synthetic substances such as Polystyrol,Polyvinyl alcohol, Polyvinyl chloride, Polyvinyl acetate, Polyvinylnitrile, Polyethylene terephtalate, Polyhexamethylenediaminadipate.Poly-E-aminocaprolactum, Polyurethane and so on. Also may be used arematerials without a fibrous structure, which arise by way of exampleannealing pastes, which contain carbon, silicon and so forth, or consistof suitable modifications of these elements.

Strands wound from the spools are taken via deflector rollers 21 whichare supported within a stator 22 secured to the wall 2.. The tangents ofrollers 21 lying nearest to the axis of the machine, and extendingparallel thereto, lie on an imaginary cylinder. A further series ofspools 23 are supported in yokes 24 which form extension pieces of arotor 25. Rotor 25 is rotatably supported on the stator 22 through theintermediary of bearings 26. The rotor is driven by a pinion 28 meshingwith a ring gear 27 carried by the rotor. The pinion is driven by a gearwheel 29 from a motor 30.

Strands 20 from the first set of spools and strands 31 from the secondset of spools intersect and form a tubular web in the form of hose 18.The angle at which the strands intersect is determined by the rate atwhich the strands are fed, and at which the hose advances. At slowspeeds the angle is nearly 90.

The airstream emerging from nozzle 32 accelerates the fiber ladenairstream considerably so that the individual fibers are injectedforcibly into the hose wall. Depending upon the mesh size, a proportionof the fibers are decelerated and frictionally caught in the meshes. ifa plurality of layers are formed concentrically about hose 18, theinjected fibers will serve to link these and give support and strengthto the composite web.

Alternatively, these may be initially formed, a multilayer hose, or atangled layer, fleece or the like consisting of several layers, andfibers then injected as disclosed hereinbefore. The mandrel 16 supportsand guides the hose 18. The hose 18 is impregnated with a strengtheningor binding agent which is sprayed onto the hose in the vicinity of themandrel through nozzles 34 directed radially inwardly towards the hose.The mandrel can have cooling ducts or a cooled jacket, so that thestrengthening agent hardens rapidly and acts before the hose reaches acutting knife 35, which cuts the hose open along one line extendingaxially along the hose wall. The material of the hose wall is spreadapart and rolled up onto the takeup roller 36. A housing 37, surroundingthe machine has an opening for the hose 18 and the mandrel l6 andensures that the strengthening agent does not escape.

Embodiment of Figure 2: in the machine of Figure 2 a web 38 of one ormore layers of intersecting strands is fed via guide rollers 40 to aduct 41. The upper run 42 of an endless belt 43 passes through the duct.The belt carries fibers fed to it from a container 44 via a meteringdevice consisting of counterrotating brush rollers 45, 46. The speed ofthe rollers 45, 46 is adjustable, whereby the rate of flow of the fibermaterial can be varied. The fibers fall through a sieve 47 onto a pairof out-ofphase grilles 48, 49, the eccentric drive of grill 49 beingshown at 50. The grille 48 has a similar drive but out of phase by 90from the drive 50. The grills prevent agglomerations of fibers occuringso that the upper run 42 of the endless belt is evenly coated.

The duct 41 is defined between parts 51 and 53 which constitute twoelectrodes 52 and 53, the electrode 53 also forming a guide for theupper run 42 of the endless conveyor belt 43. The electrode 53 isearthed at 54, whilst the electrode 52 is under the potential of ahigh-tension direct-current source 55. Between the electrodes 52, 53there thus prevails a high-tension field, under the influence of whichthe fibers having earth potential are accelerated towards thehigh-tension electrode 52. The fibers are thereby shot into the web 38.Fibers shot through the web 38 become charged and are repelled byelectrodes 52, and are again again shot into the web. The various layersof the web are interlinked by the fibers which penetrate through itnormal to the plane of the web. Subsequent to the electrode arrangement52, 53, a strengthening agent is fed via nozzles provided in series orvia a fishtail nozzle 56, to finish the operation and provide a webhaving strength in the direction normal of its plane.

lt lies within the scope of the invention that what has been representedas a single procedure can analogously be repeated. Furthermore, the webmay be formed from elongate strands intersecting in one layer only. Iftangled layers, fleeces or similar fiber accumulations are used, thenthese can be provided in any desired thickness and be subjected to themethod in accordance with the invention, whereby the increase in thestrength in the normal direction can be achieved, which in doing can bebrought to any desired further values by application of strengtheningagents. Furthermore, the fibers need not be straight. The threadsserving as the fibers may be in the form of crinkled crepe threads withsharp reversals of direction, giving a barb formation, whereby upon theintroduction the fibers transiently deform through stretching, whilstafter the introduction the fibers again assume their crinkled form.These procedures can be fostered through aftertreatments, for instancethrough treatment of the web in a warm, moist atmosphere. For the samepurpose, the web can be passed through furnaces or for instance bysubjected to an infrared radiation, so that through such measures thecrinkling is strengthened or upon a transiently affected stretching thereturn pass again enters into the original shape. These further andadditional measures being known per se, require no diagrammaticrepresentation, but it lies in the essence of the invention that thedescribed and further measures can be realized within the spirit andscope of the present invention as a need for them occurs.

What is claimed is:

l. A method of manufacturing a fibrous fabric, wherein fibers areinjected into a fibrous web in a direction substantially normal to themajor surface of the web, and the web is impregnated with a bindingagent.

2. A method according 'to claim 1, comprising:

forming a tubular wall from intersecting strands of fiber,

injecting fibers into the tubular wall in a direction substantiallynormal to the wall,

impregnating the wall with a binding agent,

slitting the wall along an axially extending line, and unfolding thetubular wall to form a fabric lying substantially in one plane.

3. Apparatus for manufacturing a fibrous fabric comprising: means forsupporting a fibrous web, means for injecting fibers into the web in adirection substantially normal to a major surface of the web, and meansfor impregnating the web with a binding agent.

4. Apparatus as claimed in claim 3, further comprising means forproviding a fiber-carrying gas stream, and nozzle means adapted todirect said fiber-carrying gas stream towards the web.

5. Apparatus as claimed in claim 3, wherein said means for injecting thefibers into the web comprise spaced high-tension and earth-potentialelectrodes, said electrodes defining together a passage for the web; anda means for feeding fibers into said passage between the web and one ofsaid electrodes.

6. Apparatus as claimed in claim 5, comprising means for feeding the webthrough said passage, and binding agent discharge nozzle means locatedafter the passage.

7. Apparatus as claimed in claim 5, comprising an endless belt forfeeding the fibers into said passage, and means for metering fibers froma storage container onto said belt.

8. Apparatus for manufacturing a fibrous fabric, comprismg:

first feeding means for feeding a plurality of continuous fibrousstrands parallel to, and spaced about, an axis so as to define a tubularstructure formed by a plurality of axially extending strands,

second feeding means rotatably supported downstream of said firstfeeding means for feeding fibrous strands around lar structuresubsequent to the injection of fibers into the wall thereof.

9. Apparatus as claimed in claim 8, wherein said takeup means includesmeans for axially slitting the wall of said wound tubular structure,means for unrolling the slit wound tubular structure to form a flat weband a takeup roller for continuously taking up said flat web.

# i i t

2. A method according to claim 1, comprising: forming a tubular wallfrom intersecting strands of fiber, injecting fibers into the tubularwall in a direction substantially normal to the wall, impregnating thewall with a binding agent, slitting the wall along an axially extendingline, anD unfolding the tubular wall to form a fabric lyingsubstantially in one plane.
 3. Apparatus for manufacturing a fibrousfabric comprising: means for supporting a fibrous web, means forinjecting fibers into the web in a direction substantially normal to amajor surface of the web, and means for impregnating the web with abinding agent.
 4. Apparatus as claimed in claim 3, further comprisingmeans for providing a fiber-carrying gas stream, and nozzle meansadapted to direct said fiber-carrying gas stream towards the web. 5.Apparatus as claimed in claim 3, wherein said means for injecting thefibers into the web comprise spaced high-tension and earth-potentialelectrodes, said electrodes defining together a passage for the web; anda means for feeding fibers into said passage between the web and one ofsaid electrodes.
 6. Apparatus as claimed in claim 5, comprising meansfor feeding the web through said passage, and binding agent dischargenozzle means located after the passage.
 7. Apparatus as claimed in claim5, comprising an endless belt for feeding the fibers into said passage,and means for metering fibers from a storage container onto said belt.8. Apparatus for manufacturing a fibrous fabric, comprising: firstfeeding means for feeding a plurality of continuous fibrous strandsparallel to, and spaced about, an axis so as to define a tubularstructure formed by a plurality of axially extending strands, secondfeeding means rotatably supported downstream of said first feeding meansfor feeding fibrous strands around said tubular structure, and means forrotating said second feeding means around said tubular structure to forma wound tubular structure, takeup means downstream of said secondfeeding means for pulling said wound tubular structure past said secondfeeding means, a nozzle for feeding a fiber-carrying gas stream intosaid wound tubular structure, deflection means for deflecting thefiber-carrying gas stream radially outwards, and impregnation means forimpregnating said wound tubular structure subsequent to the injection offibers into the wall thereof.
 9. Apparatus as claimed in claim 8,wherein said takeup means includes means for axially slitting the wallof said wound tubular structure, means for unrolling the slit woundtubular structure to form a flat web and a takeup roller forcontinuously taking up said flat web.